It has been common in the art of joining sections of heavy thermoplastic pipe in a so-called socket and saddle connection to heat a fusion head to a temperature in excess of the softening temperature of the pipe and coupling, to press the fusion head onto the end of a pipe and inside the coupling to be joined, withdraw the head and insert the softened end of the pipe into the coupling, and inside wall of which is also softened, to fuse them together. Fittings are similarly fused to pipe. Heretofore, the temperature of the fusion head has not been controlled automatically. In some heads, a thermometer has been provided by which the actual temperature of the head can be determined, but this has required that the operator remove the head from the fusion furnace at the appropriate time if the furnace is heated sufficiently to provide satisfactory recovery time.
One of the objects of this invention is to provide a fusion furnace and fusion head assembly by which the head is heated quickly, and then maintained automatically at a desired temperature.
Another object is to provide such an assembly which is reliable and safe.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.